A Zigzag (8,0) Ni-doped B32N32 Nanotube as a New Catalyst for Generation of Hydrogen from Methylamine: a DFT Study

A zigzag (8,0) boron nitride nanotube (BNNT) with 64 atoms was chosen as the simulated model. The substitution ten 3d transition metal such as nickel in (8,0) BNNTs was investigated using density functional theory (DFT). The Ni-doped BNNTs with low dimension and high surface can be considered as a new catalyst for the generation of hydrogen from methylamine [1]. In this study, the decomposition of CH3NH2 (MA) on the surface of Ni-doped BNNTs was investigated. All the calculations were carried out with the Gaussian 09 program at the B3LYP/6-31G* level of theory. The adsorption energy (Ead) of the MA on the surface of Ni-doped BNNTs is defined as:Ead = E (MA-Ni-doped BNNT) – E (MA) – E (Ni-doped BNNT) (1)The decomposition of adsorbed MA on Ni-doped BNNTs may proceed along two pathways: CH3NH = CH2NH + H and CH3NH = CH3N + H. However, the calculations shown that the first pathway is preferable. Intrinsic reaction coordinate (IRC) calculations were performed in the forward and reverse directions to determine minimum-energy pathways. Natural population analysis (NPA) and electron density difference maps were obtained at the B3LYP/6-31G* level of theory [2]. To investigate the changes of electronic structures in the Ni-doped BNNTs caused by adsorption of CH3NH2 molecule, total density of states (TDOS) and projected density of states (PDOS) of the pristine Ni-doped BNNT and CH3NH2–Ni-doped BNNT complexes are calculated. Our results demonstrated that CH3NH2 is adsorbed molecularly on the Ni-doped BNNT surface through its nitrogen lone pair electrons with the suitable adsorption energy. The adsorption process is an exothermic reaction with a negative ΔG298 value